Effect of the Absence of Wx Genes on Flag Leaf Photosynthetic Characteristics of Wheat at the Filling Stage

Starch biosynthesis of wheat seeds was not only influenced by key enzymes but also regulated by photosynthesis, and the absence of Wx gene should affect the biosynthesis of wheat starch, may also had an impact on photosynthesis in a certain extent. Effect of Wx genes on flag photosynthetic characteristics was investigated by 8 Wx near-isogenic wheat lines in this study. The results showed that the genotype had no relation to photosynthesis, but the absence of part or all three Wx genes was influencing the flag photosynthetic characteristics greatly. The net photosynthetic rate decreased significantly in the absence of Wx-A1 and Wx-B1 genes, however, which was increased in the absence of three Wx genes. In the absence of part or all of three Wx genes, the relationship among photosynthetic indices changed and no inhabiting or stimulative action of intercellular CO2 concentration on photosynthesis was observed, filling rate and carbohydrate accumulating and water using efficiency increased, and the stomatal conductance and transpiration rate decreased. This study is of great importance for the effects of Wx gene on wheat photosynthetic characteristics, yield and researches of source-sink relationship.